Hu, Y., Leinonen, T., Myrskylä, M., & Martikainen, P. (2018). Changes in Socioeconomic Differences in Hospital Days With Age: Cumulative Disadvantage, Age-as-Leveler, or Both? The Journals of Gerontology. Series B, Psychological Sciences and Social Sciences. https://doi.org/10.1093/geronb/gbx161 (Original work published 2018)